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  1. #include<bits/stdc++.h>
  2. #define file "gtbt"
  3.  
  4. using namespace std;
  5.  
  6. #define int long long
  7. #define ld long double
  8. #define pii pair<int,int>
  9. #define pb push_back
  10. #define mp make_pair
  11. #define X first
  12. #define Y second
  13. #define lb lower_bound
  14. #define ub upper_bound
  15. #define all(x) x.begin(), x.end()
  16. #define sz(x) x.size()
  17.  
  18. const int N=1e6+5;
  19. const int NN=1e3+9;
  20. const int MOD=1e9+7;
  21. const int dx[4]={0, -1, 0, 1};
  22. const int dy[4]={-1, 0, 1, 0};
  23. const int INF=1e18;
  24. const ld eps=1e-6;
  25. const ld pi=acos(-1.0); // 48 digits
  26.  
  27. string s;
  28.  
  29. int weight(char kt) {
  30.     if (kt=='^') return 3;
  31.     if (kt=='*' || kt=='/') return 2;
  32.     if (kt=='+' || kt=='-') return 1;
  33.     return 0;
  34. }
  35.  
  36. bool isOp(char kt) {
  37.     return kt=='^' || kt=='*' || kt=='/' ||
  38.             kt=='+' || kt=='-';
  39. }
  40.  
  41. // Chuyen trung to sang hau to
  42. vector<string> solve(string sth) {
  43.     sth='('+sth+')';
  44.     stack<char> st;
  45.     vector<string> res;
  46.     string num="";
  47.     for (int i=0;i<sz(sth);i++) {
  48.         char c=sth[i];
  49.         if (c==' ') continue;
  50. //        cout<<c<<endl;
  51.         if ('0'<=c && c<='9')
  52.             num+=c;
  53.         else {
  54.             if (!sz(num)==0) {
  55.                 res.pb(num);
  56.                 num="";
  57.             }
  58.             if (c=='(')
  59.                 st.push(c);
  60.             else if (c==')') {
  61.                 while (!st.empty() && st.top()!='(') {
  62.                     res.pb(string(1,st.top()));
  63.                     st.pop();
  64.                 }
  65.                 if (!st.empty())
  66.                     st.pop();
  67.             }
  68.             else if (isOp(c)) {
  69.                     if (c=='-' && sth[i-1]=='(' && st.top()=='(')
  70.                         num+='-';
  71.                     else {
  72.                         while (!st.empty() && isOp(st.top()) && // check stack ko rong hoac st.top != '('
  73.                                 (weight(st.top())>weight(c) ||
  74.                                 (weight(st.top())==weight(c) && c!='^'))) {// a^b^c => a^(b^c) chu khong phai (a^b)^c
  75.                             res.pb(string(1,st.top()));
  76.                             st.pop();
  77.                         }
  78.                         st.push(c);
  79.                     }
  80.             }
  81.         }
  82.     }
  83.     return res;
  84. }
  85.  
  86. int to_num(string s) {
  87.     int res=0;
  88.     int start;
  89.     start=(s[0]=='-' ? 1 : 0);
  90.     for (int i=start;i<sz(s);i++)
  91.         res=res*10+(s[i]-'0');
  92.     return (start ? -res : res);
  93. }
  94.  
  95. double calc(vector<string> v) {
  96.     if (sz(v)==1) return to_num(v[0]);
  97.     vector<double> st;
  98.     for (int i=0;i<sz(v);i++) {
  99.         string t=v[i];
  100.         if (isOp(t[0]) && sz(t)==1) {
  101.             double a, b;
  102. //            cout<<sz(st)<<endl;
  103. //            for (int x : st)
  104. //                cout<<x<<" ";
  105. //            cout<<endl;
  106.             b=st.back();
  107.             st.pop_back();
  108.             a=st.back();
  109.             st.pop_back();
  110.             if (t[0]=='+') st.pb(a+b);
  111.             if (t[0]=='-') st.pb(a-b);
  112.             if (t[0]=='*') st.pb(a*b);
  113.             if (t[0]=='/') st.pb(a/b);
  114.             if (t[0]=='^') st.pb(pow(a,b));
  115.         }
  116.         else {
  117.             int num=to_num(t);
  118.             st.pb(num);
  119.         }
  120.     }
  121.     return st.back();
  122. }
  123.  
  124. void process() {
  125.     // Code here :V
  126.     cout<<setprecision(6)<<fixed;
  127.     getline(cin,s);
  128.     int i=0;
  129.     while (i<sz(s)) {
  130.         if (s[i]==' ') s.erase(i,1);
  131.         else i++;
  132.     }
  133.     vector<string> t=solve(s);
  134. //    for (int i=0;i<sz(t);i++)
  135. //        cout<<t[i]<<" ";
  136. //    cout<<endl;
  137.     cout<<calc(t);
  138. }
  139.  
  140. signed main() {
  141.     cin.tie(0)->sync_with_stdio(0);
  142. //    freopen(file".inp","r",stdin);
  143. //    freopen(file".out","w",stdout);
  144.     int t=1;
  145. //    cin>>t;
  146.     while (t--) process();
  147.     return 0;
  148. }
  149.  
Success #stdin #stdout 0.01s 5284KB
comments (?)
stdin 
(-123 * 45 - 6789) / (23 + 54) ^ 2 + 1024 / (-5 + 3)
stdout 
-514.078597
https://ideone.com/z8ecWA
language:
C++14 (gcc 8.3)
created:
7 days ago
visibility:
public

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